RELATIONSHIP OF THE PELARGONIUM FLOWER BREAK CARMOVIRUS (PFBV) COAT PROTEIN GENE WITH THAT OF OTHER CARMOVIRUSES

The 3'-terminal 1500 nucleotides of the genome of pelargonium flower b reak carmovirus (PFBV) were sequenced from RT-PCR amplification produc ts. One large ORF was found, encoding a 345 amino acid protein of Mr 3 7 kDa, which corresponds to the coat protein, as confirmed by immunopr ecipitation of products of in vitro transcription and translation. The sequence also included the putative promoter of the coat protein gene subgenomic RNA, as well as its 5' and 3' untranslated regions. The PF BV coat protein was more similar to that of saguaro cactus virus and c arnation mottle virus than to that of other carmoviruses. Despite the lower level of similarity of CP gene sequences compared to the RNA dep endent RNA polymerase (RdRp) gene sequences of small icosahedral virus es used in taxonomic studies, PFBV CP sequence comparisons and alignme nts confirmed that PFBV is related to carmoviruses, tombusviruses and a dianthovirus, as previously concluded from the analysis of a PFBV Rd Rp gene fragment.